METHOD

1. Make a dough by mixing together the flour, eggs, a pinch of salt and the water. Beat until air pockets form. Leave to stand for half an hour so that the flour can expand.
2. While the batter is resting, fry the onion rings in the butter.
3. Spread the dough onto a wooden board and scrape off small slices into the boiling water to form the spätzle. Or, to make life easier, you could use what Germans call a Spatznhobel, or 'noodle slicer'. 
4. As soon as the spätzle rise to the surface, lift them out with a slotted spoon and drain. In a pre-warmed dish, place alternate layers of spaetzle and grated Allgaeuer Emmentaler cheese. Finish with a layer of spaetzle and top with the fried onions.